Humidity controller



April 3,1934. A. RUSSELL El AL 7 1,953,727

HUMIDITY CONTROLLER 2 Sheets-Sheet l Filed De c. 21. 1932 VI Imfera gEmmi/mi! N23"! 3, E A RUSSELL ET AL HUMIDITY COMROLLER Filed Dec. 21.1932 2 Sheets-Sheet 2 9 59 WET BULB 57 WET BULB 58 n 50mm BULB Im/ent);

Patented Apr. 3, 1934 UNITED STATES PATEN r OFFICE 1,953,721 HUMIDITYCONTROLLER Edward A. Russell, Chicago, Paul B. Parks, Oak

Park, and William M. Smith, Chicago, 111., assignors to Vapor CarHeating Company, Inc., Chicago, 111., a corporation of New YorkApplication December 21, 1932, Serial No. 648,232

18 Claims.

This invention relates to certain new and useful improvements inhumidity controlling apparatus, more particularly to apparatus adaptedto be used in connection with a temperature reg-' ulating system forcontrolling the relative humidity in the air within an enclosed spacesuch as a railway car.

While the invention in the form here shown by way of example isespecially adapted for use in a railway car, the principal featuresthereof are equally adaptable for controlling the humidity in othertypes of enclosures. Briefly described, means is provided forcirculating air from the enclosed space through a passage and thenceback into the space. A sprayer, or other equivalent means for projectingadditional moisture into the air, is positioned in this passage, and thepump for supplying water to the sprayer is driven by an electricmotor,the operation of the motor being controlled by a humidostat positionedin the passage adjacent its entrance, that is in advance of the sprayingdevice. This humidostat is in the form of a plurality of mercury-tubethermostats, certain .of which are of the wet-bulb 33 type so that thetemperature recorded by the thermostat will vary according to the rateat which water is vaporized from a constantly moistened wick enclosingthe bulb of the thermostat. A radiator, operating in conjunction withthe heat- 33 ing system within the enclosed space, is also positioned inthe passage so as to heat the air circulated through the passage, and aheat exchanger is provided in connection with this radiator forpre-heating the water delivered to the sprayer. Refrigerating means mayalso be positioned in the passage for cooling the air when suchtreatment is desirable.

The principal object of this invention is to provide an improvedhumidity controlling ap- :13 paratus of the type briefly describedhereinabove and disclosed more in detail in the specifications whichfollow.

Another object is to provide a humidifying apparatus controlled by a wetbulb mercury tube thermostat.

Another object is to provide a humidify'ing apparatus controlled by apair of wet-bulb thermostats functioningso that the humidifier willoperate to add moisture to the air until the wet bulb 5; temperatureexceeds. a certain predetermined maximum, and will then be caused tocease operating until the wet bulb temperature has fallen below acertain predetermined minimum, whereupon the humidifier will again beplaced in operation and will continue to operate until the predeterminedmaximum wet bulb temperature has again been reached.

Another object is to provide an improved controlling, means for ahumidifier of the type described above comprising a dry bulb thermostatfunctioning to prevent the operation of. the humidifier when the drybulb temperature falls be- Another object is to provide an improvedelectric control circuit for a humidifying apparatus.

Other objects and advantages of this invention will be more apparentfrom the following detailed description of one approved form ofapparatus constructed and operating according to the principles of thisinvention.

In the accompanying drawings:

Fig. l is a longitudinal vertical section througha portion of a railwaycar equipped with this improved humidifying system.

Fig. 2 is a perspective view showing the radiator and water-preheater.

.Fig. 3 is a side elevation, partially in vertical section, showing thethermostat assembly.

Fig. 4 is a front elevation of the assembly shown in Fig. 3, alsopartially in vertical section.

Fig. 5 is a wiring diagram showing the thermostatically controlledcircuit governing the operation of the pump-motor.

Referring first to Fig. l, the railway car indicated generally at lencloses the usual space or chamber 2, and it is the function of theapparatus hereinafter described to regulate the temperature and humidityof .the air within this chamber 2. The passage or chamber 3, usuallypositioned in one upper end portion of the car, houses the principalelements of the humidifying apparatus and also certain temperatureregulating apparatus. The fan or blower 4 draws air into passage 3through the inlet opening 5 covered by grille 6 and projects this airback into the chamber 2, preferably through a discharge passage 7provided with a plurality of grilled outlet ports 8 positioned atdifierent locations throughout the length of the car. A certainproportion of additional fresh air may be drawn in from outside the carthrough the valved inlet port 9 and carried through the and temperatureregulating apparatus and then projected into the car through thedischarge ports 8.

At 10 is indicated one of the radiators for heating the air "withinchamber 2, the supply of heating medium to this radiator, or group ofradiators, being controlled by the valve indicated at 11. A radiator 12(see also Fig. 2) is positioned within the passage 3 and supplied withheating medium through the pipe 13 leading from the distributing valve14, the heating medium and condensate returning through pipe 15 from theradiator 12 to the valve 14 and thence to the.

vapor regulator, when a vapor heating system of well known type is used.While a steam or vapor heating system is here shown by way of example,it is to be understood that other types of heating systems might be usedin connection with the improved humidifying system hereinafterdisclosed. The valves 11 and 14 may be automatically controlled, eitherseparately or jointly by means of thermostatic apparatus responsive totemperature changes within the chamber 2, as is used in such systems.The radiator 12 merely functions to temper the air circulated t roughpassage 3, the air being further heated by the system indicatedgenerally at 10 after'it is discharged into the chamber 2. When it isdesirable to cool instead of to heat the air, a suitable refrigeratingsystem may be used to Withdraw heat from the 'air circulating throughpassage 3, such heat-absorbers being indicated by the coils shown at 16and 17. It will be understood, of course, that the refrigerating systemand the heating system are not intended to be used simultaneously. Theeliminator plates indicated at 18'and 19 are for the purpose of cleaningor removing dust from the air circulated through passage 3. Thesedevices may be cf any suitable form, for example spaced screens withcopper-wool therebetween, as well mnown in the art.

For the purpose of adding moisture to the air, a suitable sprayingdevice indicated generally at 20 is positioned at'some intermediatelocation in passage 3, for example as here shown between the twocleaning devices 18 and 19. The sprayer comprises a plurality of nozzles21 through which the water is discharged into the air, the water beingsupplied to the sprayer through. 'pipe 22. The water discharged by thesprayer in excess of that taken up by the air is collected in a suitablepan 23. .A drain pipe 24 has its upper open inlet end 25 positioned asuitable distance below the top of pan 23 so that a substantiallyconstant water level will be maintained within the pan. The excessliquid drains down through pipe 24 into a make-up" or collecting tank26, usually positioned beneath the car. Water is withdrawn from tank 26by pump 27 and forced up through pipe 23- to the spraying device. Thepump 27 is driven by a motor 29. Theoperation of this motor isthermostatically controlled, as hereinafter described, and when themotor is at, rest the sprayer 20 ceases to operate.

Referring now more particularly to Fig. 2, it will be noted that thewater supply pipe 28 leading from pump 27 connects into the pre-heater30 from which leads the pipe 22 which supplies water to the sprayer 20.The pre-heater 30 is also connected into the return pipe 15 leading fromradiator .12. The pre-heater is of well known type comprising twointimately adjacent but non-communicating passages or sets of passagesthrough one of which flows the heating medim and condensate from theradiator 12, and

through the other of which flows the water supply for the sprayer. Heatwill be transferred from the vapor or condensate 'to raise thetemperature of the water flowing to the spraying device so that thetemperature of this water will more nearly approximate that of the airinto which it is discharged.

The operation of the pump motor 29 is controlled by a thermostaticassembly or humidostat indicated generally at 31 (see Fig. l) positionedin passage 3 near its inlet end so as to register the temperature andrelative humidity of the air drawn into thispassage through inlet 5 andinlet 9. The air drawn by fan 4 through the spraying and temperatureadjusting mechanisms wil pass in contact with this humidostat. Thisthermostatic assembly is shown more in detail in Figs. 3, 4 and 5 andcomprises, in the present example, three separate thermostats 32, 33 and34 of the mercury tube type. Each of these thermostats, like an ordinarythermometer, comprises a bulb 35 containing a quantity of mercury and aclosed tube/36 extending upwardly from the bulb in which a mercurycolunm 3'1 wi l rise and fall with temperature changes. Each thermostatis provided with a lower contact member which is in constant engagementwith the mercury column and an upper contact member with which themercury column will engage at a certain predetermined temperature. Acontrol cir cult is completed through the thermostat when the mercurycolumn is in contact with both of the fixed contact members. Thethermostat 32 indicates the ordinary dry bulb temperature of the airpassing in contact therewith and its upper fixed contact 38 is sopositioned that the mercury colmn will engage therewith at a certainminimum temperature, for example Fahrenheit. The control connections(hereinafter described) are such that the humidifier will not beoperative unless the dry bulb temperature ofthe air is above 60, or thetemperature for which thermostat 32.

is adjusted. The bulbs 35 of thermostats 33 and 34 are enclosed by wicks39 and 40 which are constantly supplied with water so that thesethermostats will register wet-bulb temperatures. Some of this water willbe evaporated and carried away by the air flowing in contact with thethermostat, thus withdrawing heat from the bulb and causing a lowertemperature to be registered by the thermostat. It will be apparent thatthe drier the air, or the lower its relative humidity, the higher willbe the rate of evaporization from the wick and the more will thethermostat reading be loweredbelow a corresponding dry bulb reading. Thehigher the relative humidity of the air, that is the more moisturealready in suspension in the air, the lower will be the rate ofevaporization from the wick and the less will be 59 Fahrenheit whereasthe thermostat 34 will complete its circuit at a somewhat lower wet-bulbtemperature, for example 57 Fahrenheit. These wet-bulb temperaturescorrespond approximately to a dry-bulb temperature of 70 Fahrenheit whenthe air has a desired relative humidity of approximately 50%.

The group of thermostats is preferably supported on apanel 43 carried bya suitably support ed bracket member 44 (see Figs. 3 and 4). The lowerportions of wicks 39 and 40 extend into a receptacle 45 which isconstantly filled to a certain level with water, preferably by beingconnected with pan 23 through a pipe connection 46,

Fig. l. The receptacle might be a part of the pan 23 it only beingessential that the wicks 39 and 40 be constantly maintained in amoistened condition.

The actuating and control circuits for pump motor 29 are shown in Fig.5. When the relay coil 47 is energized, the core 48 will be drawn intothe coil, and through stem 49 will close'a main switch 50 and open anauxiliary switch 51. An actuating circuit for the motor will now becompleted as follows: From positive main 52 through wire 53, main switch50, wire 54, pump motor 29, and wire 55 tothe negative main 56. When thecoil 47 is deenergized, or insufficiently energized, the core 48 andstem 49 will bemoved in the opposite direction by a suitable springmeans or by gravity so as to open the main switch 50 and close theauxiliary switch 51. This will cause the pump motor 29 to ceaseoperating. The relay coil 47 may normally be energized by currentflowing over the following circuit: From positive main 52 throughresistance 57, terminal 58, coil 47, terminal 59, wire 60, wire 61,thermostat 32, wire 62, resistance 63, and negative main 56. Theresistances 57 and 63 are simply to cut down the strength of the currentflowing throughthe relay coil and thermostats. It will be noted thatcurrent cannot flow over this circuit when the dry-bulb thermostat 32registers a temperature below Fahrenheit since the circuit will bebroken through this thermostat. A very high resistance 64 is shuntedacross the thermostat 32 to prevent arcing when the circuit through thisthermostat is broken. This resistance is too. high to prevent the flowof suificient current to cause the solenoid 47 to function.

With the parts in the positions shown in Fig. 5, the dry-bulbtemperature is above 60.Fahrenheit but the wet-bulb temperature is below59 Fahrenheit, indicating that there is insufficient moisture in theair. The solenoid 47 is energized and main switch 50 is closed so thatthe pump motor 29 will operate to cause the sprayer 20 to function andthe humidity of the air is being increased. When the relative humidityof the air has been raised to the desired percentage, the wet-bulbthermostat'33 will register a' temperature of 59 thus completing a shuntcircuit around the solenoid coil 47 as follows: From terminal 58 throughwire 65, wire 66, thermostat 33, and wire 60 to the terminal 59. Thiswill cause the relay to be deenergized so that the main switch 50 willbe opened and the pump motor will cease to operate. If only the singlewet-bulb thermostat 33 were used, as soon as the wet-bulb temperaturehad fallen below 59 Fahrenheit this shunt circuit would bebroken and therelay would again be energized to start the operation of the pump.However, at the same time that the main switch 50 is opened theauxiliary switch 51 is closed to complete a second shunt circuit throughthermostat 34 as follows: From terminal 58 through wire 65, auxiliaryswitch 51, wire 67, thermostat 34,.

operate unless the dry-bulb temperature of the air is above 60, or thetemperature for which thermostat 32 is adjusted. Below thistemperahumidity falls below 45 percent to 50 percent in which case thewet-bulb temperature will fall below 57, or the temperature for whichthermostat 34 is adjusted. In this event the pump motor will be startedand water will be forced through the sprayer 20. The humidifier willcontinue to function until the wet-bulb temperature has risen to orabove 59 whereupon the pump will be stopped and the sprayer will remaininoperative until the wet-bulb temperature'again falls below 57. The useof the two wet-bulb thermostats 33 and 34 prevents a spasmodic on andoff operation of the sprayer since the sprayer will continue to functionfor a sufficient period of time to be effective while the wet-bulbtemperature is rising between 57 and 59, and the sprayer will be keptout of operation while the wet bulb temperature is falling between 59and Approximately 25% of fresh air isusually admitted to the car throughinlet 9, and it will be noted that this fresh air is mixed with the airdrawn into passage 3 through inlet 5 from chamber 2, and that thethermostat assembly 31 is responsive to the temperature and humidity ofthis air mixture. After this air has been humidithe outside temperatureis such that the air within the car is to be cooled instead of heated,the heating system will obviously be inoperative and the refrigeratingsystem will be operated to reduce the temperature of the air streamflowing through passage 3 by means of the refrigerating coils 16 and 17.V

We-claim:

l. A humidifying apparatus comprising a device for distributing water, amotor for operating the device, an actuating circuit for the motor, amain switch in the actuating circuit, and control mechanism for openingand closing the main switch comprising a relay which when energizedholds the main switch closed, a normally closed energizing circuit forthe relay, a shunt circuit for short-circuiting the relay, and a wet-,bulb mercury tube thermostat in the shunt circuit.

2. A humidifying apparatus comprising a device for distributing water, amotor for operating the device, an actuating circuit for the motor, a

main switch in the actuating circuit, and control mechanism for openingand closing the main switch comprising a relay which when energizedholds the main switch closed, a normallyclosed energizing circuit forthe relay, a shunt circuit for short-circuiting the relay, a wet-bulbmercury tube thermostat in theshunt circuit, va second circuit shuntedaround the relay, a second wet-bulb mercury tube thermostat in thissecond shunt circuit and operative .to close its circuit at a lowertemperature than the first mentioned thermostat, and a switch-in thesecond shunt circuit that is closed by the relay when it is deenergizedand. the main switch is opened.

3. A humidifying apparatus comprising a device for distributing water, amotor for operating the device, an actuating circuit for the motor, amain switch in the actuating circuit, and control mechanism for openingand closing the main switch comprising a relay which when energizedholds the main switch closed, a normally closed energizing circuit forthe relay, a shunt circuit for short-circuiting the relay, a wet-bulbmercury tube thermostat in the shunt circuit, and a dry-bulb thermostatpositioned in the relay energizing circuit and operative to open thiscircuit when the dry-bulb temperature falls below a predeterminedminimum.

4. A humidifying apparatus comprising a device ior distributing water, amotor for operating the device, an actuating circuit for the motor, amain switch in the actuating circuit, and control mechanism for openingand closing the main switch comprising a relay'which when energizedholds the main switch closed; a normally closed energizing circuit forthe relay, a shunt circuit for short-circuiting the relay, a wet-bulbmercury tube thermostat in the shunt circuit, a second circuit shuntedaround the relay, a second wetbulb mercury tube thermostat in thissecond shunt circuit and operative to close its circuit at a lowertemperature than the first mentioned thermostat, a switch in the secondshunt circuit that is closed by; the relay when it is deenergized andthe main switch is opened, and a dry-bulb thermostat positioned in therelay energizing cir= cuit and operative to open this circuit when thedry-bulb temperature falls below a predetermined minimum.

5, Apparatus for controlling the humidity within an enclosed spacecomprising an air passage communicating with the space, means forcirculating air through the passage, means for distributing water into.the air within the passage, and means for controlling the distributingmeans comprising a pair of wet-bulb mercury tube thermostats positionedin the passage, one thermostat functioning to put the distributingdevice in operation at a predetermined wet-bulb temperature, and theother functioning to stop the operation of the distributing device at asecond predetermined wet-bulb temperature.

6. Apparatus for controlling the humidity within an enclosed spacecomprising an air passage communicating with the space, means forcirculating air through the passage, means for distributing water intothe air within the passage comprising a pump, a motor for driving thepump, an actuating circuit for the motor, andxmeans for opening andclosing the motor circuit comprising a relay, a control circuit for therelay, and a wet-bulb mercury tube thermostat positioned in the passageand connected in the control circuit. I

7., Apparatus for controlling the humidity within an enclosed spacecomprising an air pas-- sage communicating with the space, means forcirculating air through the passage, means for distributing water intothe air within the passage comprising a pump, a motor for driving thepump,

an actuating circuit for the motor, means for opening and closing themotor'circuit comprising a relay, a control circuit for the relay, and apair. of wet-bulb mercury tube thermostats positioned in the passage andconnectedin the control circuit, one thermostat functioning to cause themotor to be actuated at one predetermined wetbulb temperature and theother functioning to stop the motor at a predetermined higher wetbulbtemperature.

8. Apparatus for controlling the humidity within an enclosed spacecomprising an air passage communicating with the space, means forcirculating air through the passage, means for distributing water intothe air within the passage comprising a pump, a motor for driving thepump, an actuating circuit for the motor, means for opening and closingthe motor-circuit comprising a relay, a control circuit for the relay,and a pair of wet-bulb mercury tube thermostats and a drybulb thermostatall positioned within the passage, one wet-bulb thermostat functioningto cause the motor to be actuated at one predetermined wetbulbtemperature, the other wet-bulb thermostat determined higher wet-bulbtemperature, and the dry-bulb thermostat functioning to preventoperation of the motor when the dry-bulb temperature of the air withinthe passage falls below a predetermined minimum.

9. Apparatus for controlling the humidity within an enclosed spacecomprising an air passage communicating with the space, means forcirculating air through the passage, means positioned within the passagefor changing the temperature of the air circulating therethrough, meansfor distributing water into the air within the passage comprising apump, a motor for driving the pump, an actuating circuit for the motor,means for opening and closing the motor circuit comprising a relay, acontrol circuit for the relay, and a pair of wet=bulb mercury tubethermostats and a dry-bulb thermostat all positioned within the passage,one wet-bulb thermostat functioning to cause the motor to be actuated atone predetermined wet-bulb temperature, the other wetbulb thermostatfunctioning to cause the motor tostop at a predetermined higher wet-bulbtemperature, and the dry-bulb thermostat function I ing to preventoperation of the motor when the dry-bulb temperature of the air withinthe passage falls below a predetermined minimum.

10, Apparatus for controlling the humidity within an enclosed spacecomprisng an air passage communicating with the space, means forcirculating air through the passage, a radiator within the passage forheating the air passing therethrough, supply and return pipes for de- Ipreheating the water to be sprayed, a pump for forcing water to thespraying device, a motor for driving the pump, and a humidostatpositioned in the passage for controlling the operation of the motor.

11. Apparatus for controlling the humidity within an enclosed spacecomprising an air passage communicating with the space, means forcirculating air through the passage, a radiator within the passage forheating the air passing therethrough, supply and return pipes fordeliver= ing heating medium to and from the radiator, 1

iorcing water to the spraying device, a motor for driving the pump, acontrol circuit for the motor, a wet-bulb mercury .tube thermostatpositioned in the passage and connected in the control circuit, saidthermostat comprising a wick, and means for moistening the wick fromwater discharged from the spraying device.

12. Apparatus for controlling the humidity within anenclosed spacecomprising an air passage communicating with the space, means forcirculating air through the passage, and means for adding moisture tothe air comprising a spraying device in the passage, a pan forcollecting the water sprayed in excess of that absorbed by the air, atank, an overflow drain pipe leading from the pan to the tank, a pumpfor forcing water from the tank to the spraying device, a motor fordriving the pump, a control circuit for the motor, and a wet-bulbmercury tube thermostat positioned in the passage and connected in thecontrol circuit, the thermostat comprising a wick which is moistenedfrom the water collected in the pan.

13. Apparatus for controlling the humidity within an enclosed spacecomprising an air passage communicating with the space, means forcirculating air through the passage, and means for adding moisture tothe air comprising a spraying device in the passage, a pan forcollectingthe water sprayed in excess of that absorbed by the air, atank, an overflow drain pipe leading from the pan to the tank, a pumpfor forcing water from the tank to the spraying device, a motor fordriving the pump, a control circuit for the motor, and a wet-bulbmercury tube thermostat positioned in the passage and connected in thecontrol circuit, and a receptacle connected with the pan-and suppliedwith water therefrom, the

' thermostat comprising a wick which extends into'teriromthetanktothedevicaamotnr for driving the pump, a control circuitfor the motor,a.ndapmrorwet-bull:mercurytuliethermostatspositionedintheandconnected 'inthecontrolcircuihandaeconnected with the panand'suppliedwith water therefrom,eachthermostatcomprlsingawickwhichextends into thewaterwithinthereceptacle.

A difyml appu'etus a de- Vice m m water, controlled mlyinsmmm device,said an actuating circuit, a mainswitch in the actuating circuit,

and control mechanism for opening and closing the main switch comprisinga relay which when energized holds the main switch closed, 9. normallyclosed energizing circuit for the relay, a shunt-circuit forshort-circuiting the relay, and a wet-bulb mercury-tube thermostat intheshunt circuit.

' 16. A humidiiying apparatus comprising a device for distributingwater, electrically controlled mechanism for supplying water to thedistributing device, said mechanism comprising an actuating circuit, amain switch in the actuating circuit, and control mechanism for openingand closing the main switch comprising a relay which when energizedholds the main switch closed, 9. normally closed energizing circuit forthe relay, a

shunt-circuit tor short-circuiting the relay, a wet-bulb mercury-tubethermostat in the shunt circuit, a second circuit shunted around therelay, a second wet-bulb mercury tube thermostat in this second shuntcircuit and operative to close its circuit at a lower temperature thanthe first mentioned thermostat, and a switch in .the second shuntcircuit that is closed by the mostat in the shunt circuit, and a drybulb thermostat positioned in the relay energizing circuit and operativeto open this circuit when the dry bulb temperature falls below apredetermined 18, A humidiiying apparatus comprising a device fordistributing water, electrically controlled mechanism for supplyingwater to the distributing device, said m comprising an actuatingcircuit, a main switch in the actuating circuit,

and control for opening and clomng the main switch comprising means forholding theswitchclosedwhile the wet-bulb temperatureoitheairisrisingtromaminimumtoapredeterminedmaximmmeanscomm tmemmuibetfor openimthemainswitchwhmthe '1 umazlmmnw'et-bulbtemperatureisreachedand meansaseeondwet-bulb'thnrmostatforholdingthe'switchopenwhilethewet-bulb temperatme is falling totheminimum nnw'snn s;

' PAULB.PARKB. *wnumnsm'm.

